Rapid quench line

ABSTRACT

A rapid quenching line can be suitable for use with hot coil at, or above the metal strip&#39;s recrystallization point. Hot coil can be uncoiled by a low tension uncoiler using a non-contacting hold-down device. The metal strip coming off the hot coil is rapidly quenched (e.g., at rates of at or above 100° C./s or 200° C./s) through multiple quenching zones. Coolant can be removed, such as with an air knife and/or a wiper (e.g., an ultra-compliant wiper). Steam can be collected from earlier quenching zones and be repurposed to provide humid air to the metal strip, such as at regions where the temperature of the metal strip is at or below the Leidenfrost point. The cooled metal strip can pass through a bridle to increase the tension in the metal strip before the metal strip is optionally lubricated and then recoiled or otherwise further processed.

REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/915,915, filed on Oct. 16, 2019 and entitled RAPIDQUENCH LINE, the content of which is hereby incorporated by reference inits entirety.

TECHNICAL FIELD

The present disclosure relates to metalworking generally and morespecifically to controlling temperature of metal articles duringproduction of the metal articles.

BACKGROUND

The metallurgical structure of a metal article can have substantialimpact on various properties of the metal article, such as the metalarticle's strength and/or formability. During production processes, caremust be taken to ensure the metal article being produced has the desiredmetallurgical properties. Precise control of a metal article'stemperature during production of the metal article can enable the metalarticle to be produced with the desired metallurigal properties anddesired metallurgical structure.

Direct chill (DC) and continuous casting are two methods of castingsolid metal from liquid metal. In DC casting, liquid metal is pouredinto a mold having a retractable false bottom capable of withdrawing atthe rate of solidification of the liquid metal in the mold, oftenresulting in a large and relatively thick ingot (e.g., 1500 mm×500 mm×5m). The ingot can be processed, homogenized, hot rolled, cold rolled,annealed and/or heat treated, and otherwise finished before being coiledinto a metal strip product distributable to a consumer of the metalarticle (e.g., an automotive manufacturing facility).

Continuous casting can include continuously injecting molten metal intoa casting cavity defined between a pair of moving opposed castingsurfaces and withdrawing a cast metal article (e.g., a metal strip) fromthe exit of the casting cavity. Continuous casting can produce metalarticles of any suitable length, which can be especially suitable forproducing coilable metal strip.

Often, a metal article must be thermally processed to achieve desiredmetallurgical structure and/or metallurgical properties. Examples ofsuch thermal treatments include high-temperature annealing orhomogenization, which both involve heating the metal article torelatively high temperatures. Annealing is a high-temperature processperformed on a worked (e.g., work hardened) metal article, often attemperatures at or near the metal's recrystallization temperature (e.g.,around 300-400° C. for some types of Aluminum alloy). Homogenization isa high-temperature process performed on metal articles to reduce thegrain-level heterogeneity of an as-cast microstructure. Homogenizationis often performed at temperatures above the metal's recrystallizationtemperature, such as temperatures of around 450-600° C. in some types ofAluminum alloy, dependent on the alloy's system. When heated to theseranges of temperatures (e.g., at or above the recrystallizationtemperature), the metallurgical microstructure of the metal article canbecome more homogenous, improving the formability of the metal articleand/or other metallurgical properties. However, at these hightemperatures, the metal article is especially susceptible to damage ifmistreated. Often, annealing or homogenization is performed on DC castingots.

Annealing or homogenization for metal strip, such as coiled metal strip,often requires the use of a continuous annealing and solution heattreatment (CASH) line. These CASH lines occupy a very large footprintand require many specialized pieces of equipment designed to uncoil themetal strip, levitate the metal strip through furnaces and coolingzones, and re-coil the metal strip. Without levitating the metal strip,physical contact with rollers or the like may harm the delicate metalstrip when the metal strip is at elevated temperature. The path taken bythe metal strip through the CASH line is often long and circuitous,requiring long lengths of metal strip to be scrapped due to the need tothread the metal strip through the CASH line to begin processing it.Additionally, to avoid having to scrap these large amounts of metalstrip for each coil, CASH lines often require the use of accumulatorsand cutters to combine separate coils together into a continuous metalstrip and then cut the continuous metal strip into separate, processedcoils.

SUMMARY

The term embodiment and like terms are intended to refer broadly to allof the subject matter of this disclosure and the claims below.Statements containing these terms should be understood not to limit thesubject matter described herein or to limit the meaning or scope of theclaims below. Embodiments of the present disclosure covered herein aredefined by the claims below, not this summary. This summary is ahigh-level overview of various aspects of the disclosure and introducessome of the concepts that are further described in the DetailedDescription section below. This summary is not intended to identify keyor essential features of the claimed subject matter, nor is it intendedto be used in isolation to determine the scope of the claimed subjectmatter. The subject matter should be understood by reference toappropriate portions of the entire specification of this disclosure, anyor all drawings and each claim.

Embodiments of the present disclosure include a system, comprising: alow-tension unwinding unit for receiving and unwinding a metal coil ofmetal strip; a non-contacting hold-down device positioned adjacent thelow-tension unwinding unit to provide force on the metal strip towardsthe center of the metal coil during unwinding of the metal coil; a setof quenching zones for cooling the metal strip, wherein the set ofquenching zones provides sufficient coolant to reduce a temperature ofthe metal strip by a rate of at least 100° C. per second; a coolantremoval unit positioned downstream of the set of quenching zones; and abridle unit positioned downstream of the coolant removal unit forincreasing tension in the metal strip.

In some cases, the low-tension unwinding unit comprises insulationdisposed to retain heat within coiled portions of the metal coil. Insome cases, the low-tension unwinding unit comprises a heat source forproviding heat to coiled portions of the metal coil, wherein the heatsource is coupled to a controller for maintaining the metal coil at orabove a threshold temperature. In some cases, the non-contactinghold-down device comprises one or more magnets for generating a changingmagnetic field through the metal strip. In some cases, the changingmagnetic field is configured distribute the force over time across awidth of the metal strip. In some cases, the non-contacting hold-downdevice comprises a nozzle for blowing heated air against the metalstrip. In some cases, the system further comprises: a flatnessmeasurement unit positioned to measure a flatness of the metal strip;and a controller coupled to the flatness measurement unit and the set ofquenching zones to adjust delivery of the coolant based on measuredflatness of the metal strip. In some cases, the system further comprisesa stabilization system positioned upstream of the set of quenching zonesto introduce a wave into the metal strip. In some cases, the metal stripremains supported without mechanical contact between the metal coil andthe coolant removal unit. In some cases, the set of quenching zonescomprises a steam reclamation module for redirecting humid air from atleast one of the set of quenching zones to the metal strip at a locationdownstream of the at least one of the set of quenching zones. In somecases, the location downstream of the at least one of the set ofquenching zones is a location where the temperature of the metal stripis at or below a Leidenfrost point. In some cases, the system furthercomprises: a pre-quench heating unit positioned downstream of thelow-tension unwinding unit; and a controller coupled to the pre-quenchheating unit to heat the metal strip to a target temperature prior tothe metal strip entering the set of quenching zones. In some cases, thenon-contacting hold-down device is positioned to provide the force onthe metal strip at a location at or adjacent to where the metal stripfalls away from the metal coil due to gravity.

Embodiments of the present disclosure include a method, comprising:unwinding a hot metal coil using a low-tension unwinder, whereinunwinding the hot metal coil comprises applying a non-contactinghold-down force to the hot metal coil and permitting metal strip of thehot metal coil to fall away from the metal coil; rapidly quenching themetal strip in a set of quenching zones, wherein rapidly quenching themetal strip comprises applying coolant to the metal strip to reduce atemperature of the metal strip at a rate of at least 100° C. per second;removing the coolant from the metal strip; and applying downstreamtension to the metal strip.

In some cases, the method further comprises maintaining an initialtemperature of the hot metal coil at the low-tension unwinder. In somecases, the method further comprises preheating the metal stripimmediately prior to rapidly quenching the metal strip. In some cases,applying the non-contacting hold-down force comprises generating achanging magnetic field through the metal strip. In some cases, applyingthe non-contacting hold-down force comprises blowing heated air againstthe metal strip. In some cases, the method further comprises: measuringflatness of the metal strip; and adjusting delivery of the coolant basedon the measured flatness. In some cases, the method further comprisesinducing a wave in the metal strip without contacting the metal strip.In some cases, the method further comprises: capturing steam from atleast one of the quenching zones; and redirecting the captured steamtowards the metal strip. In some cases, redirecting the captured steamcomprises redirecting the capture steam towards the metal strip at alocation where a temperature of the metal strip is at or below theLeidenfrost point.

BRIEF DESCRIPTION OF THE DRAWINGS

The specification makes reference to the following appended figures, inwhich use of like reference numerals in different figures is intended toillustrate like or analogous components.

FIG. 1 is a schematic side view of a system for rapidly quenching andrecoiling a hot metal coil according to certain aspects of the presentdisclosure.

FIG. 2 is a schematic side view of a system for rapidly quenching a hotmetal coil for further rolling according to certain aspects of thepresent disclosure.

FIG. 3 is a schematic block diagram of a rapid quench line according tocertain aspects of the present disclosure.

FIG. 4 is a combination schematic block diagram and temperature graphdepicting relative temperatures of a metal strip passing through a rapidquench line according to certain aspects of the present disclosure.

FIG. 5 is a schematic side view of a steam reclamation module on a rapidquench line according to certain aspects of the present disclosure.

FIG. 6 is a schematic top view of a magnetic rotor non-contactinghold-down roll according to certain aspects of the present disclosure.

FIG. 7 is a flowchart depicting a process for rapidly quenching a hotmetal coil according to certain aspects of the present disclosure.

DETAILED DESCRIPTION

Certain aspects and features of the present disclosure relate to a rapidquenching line suitable for use with hot coil, or coiled metal strip attemperatures near, at, or above the metal strip's recrystallizationpoint. The recrystallization point can be at or approximately between40%-50% of the melting temperature of the metal strip. The rapidquenching line can include a low tension uncoiler making use of anon-contacting hold-down device. The metal strip coming off the lowtension uncoiler is rapidly quenched (e.g., at rates of at or above 30°C./s, 50° C./s, 100° C./s or 200° C./s) through multiple quenchingzones. Coolant can be removed, such as through the use of an air knifeand/or an ultra-compliant wiper. In some cases, steam collected fromearlier quenching zones can be repurposed to provide humid air to themetal strip at regions where the temperature of the metal strip is at orbelow the Leidenfrost point. The cooled metal strip can pass through abridle to increase the tension in the metal strip before the metal stripis optionally lubricated and then recoiled or otherwise furtherprocessed.

In metal production, continuous casting processes or rolling processes(e.g., hot rolling) can result in a coiled product, such as a coiledmetal strip. As disclosed herein, the term metal strip is inclusive ofmetal articles of any suitable thickness capable of being coiled, suchas a metal sheet or metal shate. A metal strip can have any suitablelength or width. In some cases, certain aspects of the presentdisclosure may be suitable for use with metal strip products that arenot necessarily coiled, although in some cases certain aspects of thepresent disclosure may be especially suitable for use with metal coils.A metal coil can comprise a metal strip coiled.

As used herein, a sheet generally refers to an aluminum product having athickness of less than about 4 mm. For example, a sheet may have athickness of less than about 4 mm, less than about 3 mm, less than about2 mm, less than about 1 mm, less than about 0.5 mm, or less than about0.3 mm (e.g., about 0.2 mm).

As used herein, terms such as “cast metal product,” “cast product,”“cast aluminum alloy product,” and the like are interchangeable andrefer to a product produced by direct chill casting (including directchill co-casting) or semi-continuous casting, continuous casting(including, for example, by use of a twin belt caster, a twin rollcaster, a block caster, or any other continuous caster), electromagneticcasting, hot top casting, or any other casting method.

As used herein, the meaning of “room temperature” can include atemperature of from about 15° C. to about 30° C., for example about 15°C., about 16° C., about 17° C., about 18° C., about 19° C., about 20°C., about 21° C., about 22° C., about 23° C., about 24° C., about 25°C., about 26° C., about 27° C., about 28° C., about 29° C., or about 30°C. As used herein, the meaning of “ambient conditions” can includetemperatures of about room temperature, relative humidity of from about20% to about 100%, and barometric pressure of from about 975 millibar(mbar) to about 1050 mbar. For example, relative humidity can be about20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%,about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%,about 40%, about 41%, about 42%, about 43%, about 44%, about 45%, about46%, about 47%, about 48%, about 49%, about 50%, about 51%, about 52%,about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, about59%, about 60%, about 61%, about 62%, about 63%, about 64%, about 65%,about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about72%, about 73%, about 74%, about 75%, about 76%, about 77%, about 78%,about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%,about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about98%, about 99%, about 100%, or anywhere in between. For example,barometric pressure can be about 975 mbar, about 980 mbar, about 985mbar, about 990 mbar, about 995 mbar, about 1000 mbar, about 1005 mbar,about 1010 mbar, about 1015 mbar, about 1020 mbar, about 1025 mbar,about 1030 mbar, about 1035 mbar, about 1040 mbar, about 1045 mbar,about 1050 mbar, or anywhere in between.

While certain aspects of the present disclosure may be suitable for usewith any type of metal, certain aspects of the present disclosure may beespecially suitable for use with aluminum. In this description,reference is made to alloys identified by AA numbers and other relateddesignations, such as “series” or “7xxx.” For an understanding of thenumber designation system most commonly used in naming and identifyingaluminum and its alloys, see “International Alloy Designations andChemical Composition Limits for Wrought Aluminum and Wrought AluminumAlloys” or “Registration Record of Aluminum Association AlloyDesignations and Chemical Compositions Limits for Aluminum Alloys in theForm of Castings and Ingot,” both published by The Aluminum Association.

Certain aspects of the present disclosure are especially suitable foruse with aluminum alloys from the 2xxx, 6xxx, 7xxx, or 8xxx series,although other alloys can be used. When certain aluminum alloys areproduced, alloying elements can form precipitates. In the case of somealloys, such as 2xxx, 6xxx, 7xxx, or 8xxx series alloys, especiallymassive precipitates can form when the aluminum alloy is being cooledfrom high temperatures, such as down to room temperature. These massiveprecipitates do not dissolve well in the aluminum product, can bedifficult or impossible to correct, and can result in undesirablemechanical properties. For example, in 6xxx series aluminum alloys,cooling from high temperatures to room temperature at traditional ratescan result in the formation of large Mg2Si precipitates, which can bedetrimental to the desired metallurgical structure of the aluminumproduct. These problems are especially prevalent when cooling fromtemperatures above a metal's recrystallization temperature, such asduring an annealing or homogenization process, down to room temperature.However, if a metal article can be cooled sufficiently quickly, such asdisclosed herein, dissolved elements that would otherwise formprecipitates can remain in a supersaturated solid solution all the waydown to room temperature.

In a homogenization step, the metal product described herein can beheated to a temperature ranging from about 400° C. to about 600° C. Forexample, the product can be heated to a temperature of about 400° C.,about 410° C., about 420° C., about 430° C., about 440° C., about 450°C., about 460° C., about 470° C., about 480° C., about 490° C., or about500° C. The product is then allowed to soak (i.e., held at the indicatedtemperature) for a period of time. In some examples, the total time forthe homogenization step, including the heating and soaking phases, canbe up to 24 hours. For example, the product can be heated up to 500° C.and soaked, for a total time of up to 18 hours for the homogenizationstep. Optionally, the product can be heated to below 490° C. and soaked,for a total time of greater than 18 hours for the homogenization step.In some cases, the homogenization step comprises multiple processes. Insome non-limiting examples, the homogenization step includes heating theproduct to a first temperature for a first period of time followed byheating to a second temperature for a second period of time. Forexample, the product can be heated to about 465° C. for about 3.5 hoursand then heated to about 480° C. for about 6 hours.

Following the homogenization step, a hot rolling step can be performed.Prior to the start of hot rolling, the homogenized product can beallowed to cool to a temperature between 300° C. to 520° C. For example,the homogenized product can be allowed to cool to a temperature ofbetween 325° C. to 425° C. or from 350° C. to 400° C. The product canthen be hot rolled at a temperature between 300° C. to 450° C. to form ahot rolled plate, a hot rolled shate or a hot rolled sheet having agauge between 3 mm and 200 mm (e.g., 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm,9 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 110mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200mm, or anywhere in between).

Optionally, the cast product can be a continuously cast product that canbe allowed to cool to a temperature between 300° C. to 520° C. Forexample, the continuously cast product can be allowed to cool to atemperature of between 325° C. to 425° C. or from 350° C. to 400° C. Thecontinuously cast products can then be hot rolled at a temperaturebetween 300° C. to 450° C. to form a hot rolled plate, a hot rolledshate or a hot rolled sheet having a gauge between 3 mm and 200 mm(e.g., 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, 25mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm,150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, or anywhere in between).During hot rolling, temperatures and other operating parameters can becontrolled so that the temperature of the hot rolled intermediateproduct upon exit from the hot rolling mill is no more than 470° C., nomore than 450° C., no more than 440° C., or no more than 430° C.

The plate, shate or sheet can then be cold rolled using conventionalcold rolling mills and technology into a sheet. The cold rolled sheetcan have a gauge between about 0.5 to 10 mm, e.g., between about 0.7 to6.5 mm. Optionally, the cold rolled sheet can have a gauge of 0.5 mm,1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm,5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm,or 10.0 mm. The cold rolling can be performed to result in a final gaugethickness that represents a gauge reduction of up to 85% (e.g., up to10%, up to 20%, up to 30%, up to 40%, up to 50%, up to 60%, up to 70%,up to 80%, or up to 85% reduction). Optionally, an interannealing stepcan be performed during the cold rolling step. The interannealing stepcan be performed at a temperature of from about 300° C. to about 450° C.(e.g., about 310° C., about 320° C., about 330° C., about 340° C., about350° C., about 360° C., about 370° C., about 380° C., about 390° C.,about 400° C., about 410° C., about 420° C., about 430° C., about 440°C., or about 450° C.). In some cases, the interannealing step comprisesmultiple processes. In some non-limiting examples, the interannealingstep includes heating the plate, shate or sheet to a first temperaturefor a first period of time followed by heating to a second temperaturefor a second period of time. For example, the plate, shate or sheet canbe heated to about 410° C. for about 1 hour and then heated to about330° C. for about 2 hours.

Subsequently, the plate, shate or sheet can undergo a solution heattreatment step. The solution heat treatment step can be any conventionaltreatment for the sheet which results in solutionizing of the solubleparticles. The plate, shate or sheet can be heated to a peak metaltemperature (PMT) of up to 590° C. (e.g., from 400° C. to 590° C.) andsoaked for a period of time at the temperature. For example, the plate,shate or sheet can be soaked at 480° C. for a soak time of up to 30minutes (e.g., 0 seconds, 60 seconds, 75 seconds, 90 seconds, 5 minutes,10 minutes, 20 minutes, 25 minutes, or 30 minutes). After heating andsoaking, the plate, shate or sheet is rapidly cooled at rates greaterthan 200° C/s to a temperature between 500 and 200° C. In one example,the plate, shate or sheet has a quench rate of above 200° C./second attemperatures between 450° C. and 200° C. Optionally, the cooling ratescan be faster in other cases. In some cases, quenching can occur using arapid quench line as disclosed herein.

After quenching, the plate, shate or sheet can optionally undergo apre-aging treatment by reheating the plate, shate or sheet beforecoiling. The pre-aging treatment can be performed at a temperature offrom about 70° C. to about 125° C. for a period of time of up to 6hours. For example, the pre-aging treatment can be performed at atemperature of about 70° C., about 75° C., about 80° C. about 85° C.,about 90° C., about 95° C., about 100° C., about 105° C., about 110° C.,about 115° C., about 120° C., or about 125° C. Optionally, the pre-agingtreatment can be performed for about 30 minutes, about 1 hour, about 2hours, about 3 hours, about 4 hours, about 5 hours, or about 6 hours.The pre-aging treatment can be carried out by passing the plate, shateor sheet through a heating device, such as a device that emits radiantheat, convective heat, induction heat, infrared heat, or the like.

The cast products described herein can also be used to make products inthe form of plates or other suitable products. For example, platesincluding the products as described herein can be prepared by processingan ingot in a homogenization step or casting a product in a continuouscaster followed by a hot rolling step. In the hot rolling step, the castproduct can be hot rolled to a 200 mm thick gauge or less (e.g., fromabout 10 mm to about 200 mm). For example, the cast product can be hotrolled to a plate having a final gauge thickness of about 10 mm to about175 mm, about 15 mm to about 150 mm, about 20 mm to about 125 mm, about25 mm to about 100 mm, about 30 mm to about 75 mm, or about 35 mm toabout 50 mm.

In some cases, it can be desirable to store hot metal strip (e.g., attemperatures at or above the metal's recrystallization temperature) inthe form of a metal coil. This hot metal coil can be a result of acontinuous casting process or a rolling process (e.g., from a continuouscast or DC cast product). The metal coil format can be useful forstoring long lengths of metal strip in an efficient manner. Rather thanpassing a long length of metal strip through a CASH line or othersimilar processing line with long lengths of furnaces and cooling zones,a single metal coil can be placed in a furnace and held at a desiredtemperature for a desired duration to achieve desired thermal processingeffects. For example, an aluminum metal coil can be kept in a furnace ataround 350° C.-400° C. for a duration to anneal the metal strip.

While hot metal coils are useful for storing long lengths of metal stripin a relatively small footprint, hot metal coils must be carefullyhandled. Whenever the metal strip is above its recrystallizationtemperature, there exists risks that undue pressure, tension, mechanicalcontact, or other forces may harm the metal strip, requiring thescrapping of some or all of the metal strip. For example, too-hightension when uncoiling a hot metal coil can result in the metal stripsustaining rips, deformation, and/or surface damage. Therefore, thehandling of hot metal coils is especially difficult. While it may bedesirable to store the metal strip as a hot coil at certain times (e.g.,during thermal processing, such as annealing or homogenization), it canbe desirable to store the metal strip as a warm or cold coil at othertimes (e.g., to facilitate handling of the metal strip, such as using aforklift or other common factory equipment). In some cases, certainequipment (e.g., hot rolling mills) require sufficient back-tension tooperate, which may be higher tension than a hot metal strip is capableof withstanding. In such cases, it can be necessary to cool the hotmetal coil to a low enough temperature such that it can be fed into thedesired equipment. As disclosed herein, the terms warm and cold refer totemperatures below the metal's recrystallization point.

Traditionally, hot metal coils may be cooled by leaving the hot metalcoil in ambient temperature at or near room temperature or by forcingair over the metal coil, permitting the hot coil to cool down over manyhours. In some cases, spraying the hot metal coils with fluids, such asrolling oil, has been attempted, but still requires hours to obtain thedesired, cooled temperature, is environmentally unfriendly, is veryexpensive, and leaves the coil soaked in rolling oil, which limits thenext operation to only a cold rolling mill. According to certain aspectsof the present disclosure, a rapid quench system can cool a hot metalcoil down to a warm or cold metal coil in a fraction of the time, suchas in a manner of minutes, in a more environmentally friendly manner,with less expense, and with little or no residual coolant remaining onthe metal strip.

According to certain aspects of the present disclosure, a low-tensionuncoiler is disclosed that can safely unwrap a hot coil. Whiletraditional coilers use tension to ensure proper pay-off of the metalstrip from a metal coil, the low-tension uncoiler makes use of thenatural pull of gravity to facilitate separating the metal strip fromthe remainder of the metal coil.

Additionally, a non-contacting hold-down device is used to applysufficient force through the metal strip and towards the metal coil tohelp control proper pay-off of the metal strip. As used herein, the termnon-contacting refers to non-mechanical-contact or a lack of physicalcontact between the metal strip and another structure. For example, anon-contacting hold-down roll can take the form of a magnetic rotor or aset of electromagnets that generates a changing magnetic field throughthe metal strip, inducing forces on the metal strip through Lenz's law,without contacting the metal strip. In another example, a non-contactinghold-down device can take the form of one or more nozzles designed toblow hot air (e.g., sufficiently hot to avoid quenching the metal strip)against the metal strip to control pay-off of the metal strip from theremainder of the metal coil. The one or more nozzles do not make contactwith the metal strip, and instead directed fluid towards the metalstrip.

In some cases, the non-contacting hold-down roll can be a magnetic rotorhaving alternating poles oriented in a chevron pattern, such that thetotal magnetic flux passing through the metal strip at any point in timeis constant or near constant. Such a chevron pattern can generate auniform force acting on the metal strip and can avoid oscillations intension.

In some cases, the non-contacting hold-down roll can be positioned atthe pay-off point (e.g., the point where the metal strip separates fromthe remainder of the metal coil), or can be positioned within 5°, 10°,15°, or 20° of the pay-off point.

As the metal strip is payed-off from the remainder of the metal coil,the curvature of the metal strip being payed-off can be measured (e.g.,through distance measurement devices or machine vision) and used tocontrol the pay-off rate of the metal coil.

In some cases, the uncoiler can be maintained at a particulartemperature, such as through the use of insulation or additional headingelements. By avoiding temperature drop in the hot coil itself,subsequent quenching steps can be more accurately performed, since thetemperature of the metal strip entering the quenching zones will berelatively stable. In some cases, a stable starting temperature for thequenching process can be optionally achieved through the use ofadditional heating elements disposed downstream of the uncoiler, whichcan heat the metal strip to a target temperature despite fluctuation inthe initial temperature of the metal strip. Such additional heatingelements can take any suitable form, such as radiant, convection,infrared, flame, or magnetic heating elements. In some cases, suchadditional heating elements can take the form of rotating magnetsdisposed adjacent the metal strip and rotating at sufficient speeds toincrease the temperature in the metal strip without contacting the metalstrip. In some cases, the non-contacting hold-down device can work inconcert with one or more additional heating elements bring thetemperature of the metal strip to a target temperature. In some cases,when an additional heating element that is a magnetic rotor or set ofelectromagnets is used, cold spots near the edges of the metal strip canbe avoided by introducing additional heat at those cold spots before orafter passing by the additional heating element. In such cases, anon-contacting hold-down device in the form of a pair of magnetic rotorspositioned adjacent the metal strip at locations just before the edgesof the metal strip can be used to introduce this additional heat toavoid cold spot formation when the metal strip passes by the magneticrotor additional heating element.

In some cases, magnetic rotors, electromagnets, and/or air nozzles canbe used to induce a wave (e.g., a sine wave) to stabilize the sheet.

The uncoiled metal strip can pass through a set of quenching zones(e.g., one or more quenching zones or two or more quenching zones). Eachquenching zone can comprise a set of spray headers (e.g., an upper sprayheader and a lower spray header) configured to deliver coolant to themetal strip. As used herein, a spray header can include a single nozzle,multiple nozzles, or any other suitable configuration. Coolant caninclude any suitable coolant, such as water, oil, air, orLeidenfrost-free fluid. The spray headers can be sized to delivercoolant to the metal strip to lower the temperature of the metal stripat rates of at or at least 100° C./s or 200° C./s. The set of quenchingzones start adjacent the pay-off point, as the metal strip is fallingflat, or can start spaced apart from the pay-off point, after the metalstrip has fallen flat. In some cases, the spray headers of one or morequenching zones can be coupled to actuators to control their relativepositions with respect to the metal strip, such as to maintain a desiredspacing between the metal strip and the spray header.

In some cases, the parameters of the set of quenching zones can beadjusted to achieve a desired quench rate that is optimized for aparticular alloy. In some cases, identification of an incoming alloy,whether automatic or manual, can be used to pre-adjust the parameters ofthe set of quenching zones.

In some cases, a steam reclamation module can collect steam from one ormore of the set of quenching zones (e.g., first one or more quenchingzones) and direct the steam to the metal strip at a point furtherdownstream. It can be especially advantageous to direct the steamtowards the metal strip at a location where the metal strip hassufficiently cooled to reach a temperature at or below the Leidenfrostpoint, although this need not always be the case. The steam reclamationmodule can optionally include a blower (e.g., fan) or other equipmentnecessary to facilitate redirection of the collected steam. The presenceof this humid air around the metal strip after the Leidenfrost pointavoids condensation on the metal strip and has more heat capacity toextract heat from the metal strip than dry air. Thus, the use ofrecaptured steam can provide a consistent environment for heatextraction through and/or after the Leidenfrost point. It has been foundthat this consistent, humid environment can protect the flatness of thecooling metal strip. In some cases, however, the steam reclamationmodule can collect and/or redirect steam away from the metal coil tohelp prevent staining of the metal strip still on the metal coil, withor without redirecting the steam to the metal strip at a point furtherdownstream.

Above the Leidenfrost point, it can be trivial to keep the surface ofthe metal strip dry, due to the speed at which the coolant boils.However, below the Leidenfrost point, it can be non-trivial to removeresidual coolant from the metal strip. Therefore, air knives can be usedto wipe coolant off the top of the metal strip (e.g., away from thecenterline and over the edges of the metal strip). In some cases, asqueegee can be used to remove excess coolant. Below the metal strip, awiper can be used, such as an ultra-compliant. An ultra-compliant wipercan include numerous actuators designed to alter the shape of theultra-compliant wiper to match the wave of the metal strip. In somecases, a lubricating spray (e.g., oil spray) can be applied to the metalstrip before reaching the wiper.

After the metal strip has been rapidly quenched and excess coolantremoved, the metal strip can pass through a device to add tension backinto the metal strip, such as a bridle. The bridle can comprise a set ofrollers around which the metal strip is wrapped to maintain tension in adownstream direction. Since the rapid quench system is especiallysuitable for processing individual hot metal rolls, it can be beneficialto use a bridle that is easy to thread, such as a bridle having lowerand/or inner rolls that can be moved away from upper and/or outer rollsto a threading position for threading, then moved back into an operatingposition for introducing tension into the metal strip.

After the bridle roll, the metal strip can optionally pass through alubricator and then pass around a deflector roll before proceeding to adesired piece of downstream equipment, such as a coiler. In some cases,the deflector roll can measure flatness of the metal strip (e.g., aflatness measuring roll). In some cases, this measured flatness can beused to provide feedback to the set of quenching zones to facilitatecontrolling flatness of the metal strip.

In some cases, the rapid quench system disclosed herein can facilitatethe production of fully solutionized metal products without the use of aCASH line, thus saving time, expense, and capital expenditure.

The aluminum alloy products described herein can be used in automotiveapplications and other transportation applications, including aircraftand railway applications. For example, the disclosed aluminum alloyproducts can be used to prepare automotive structural parts, such asbumpers, side beams, roof beams, cross beams, pillar reinforcements(e.g., A-pillars, B-pillars, and C-pillars), inner panels, outer panels,side panels, inner hoods, outer hoods, or trunk lid panels. The aluminumalloy products and methods described herein can also be used in aircraftor railway vehicle applications, to prepare, for example, external andinternal panels.

The aluminum alloy products and methods described herein can also beused in electronics applications. For example, the aluminum alloyproducts and methods described herein can be used to prepare housingsfor electronic devices, including mobile phones and tablet computers. Insome examples, the aluminum alloy products can be used to preparehousings for the outer casing of mobile phones (e.g., smart phones),tablet bottom chassis, and other portable electronics.

All ranges disclosed herein are to be understood to encompass any andall subranges subsumed therein. For example, a stated range of “1 to 10”should be considered to include any and all subranges between (andinclusive of) the minimum value of 1 and the maximum value of 10; thatis, all subranges beginning with a minimum value of 1 or more, e.g. 1 to6.1, and ending with a maximum value of 10 or less, e.g., 5.5 to 10.Unless stated otherwise, the expression “up to” when referring to thecompositional amount of an element means that element is optional andincludes a zero percent composition of that particular element. Unlessstated otherwise, all compositional percentages are in weight percent(wt. %).

As used herein, the meaning of “a,” “an,” and “the” includes singularand plural references unless the context clearly dictates otherwise.

These illustrative examples are given to introduce the reader to thegeneral subject matter discussed here and are not intended to limit thescope of the disclosed concepts. The following sections describe variousadditional features and examples with reference to the drawings in whichlike numerals indicate like elements, and directional descriptions areused to describe the illustrative embodiments but, like the illustrativeembodiments, should not be used to limit the present disclosure. Theelements included in the illustrations herein may not be drawn to scale.

FIG. 1 is a schematic side view of a system 100 for rapidly quenchingand recoiling a hot metal coil 104 according to certain aspects of thepresent disclosure. The hot metal coil 104 comprises metal strip 124 athigh temperatures (e.g., temperature at or above the recrystallizationtemperature of the metal strip 124).

The metal coil 104 can be unwound by an unwinder 102. The unwinder 102can unwind the hot metal coil 104 in unwinding direction 106. Anon-contacting hold-down device 108 can apply slight force to facilitatecontrolled pay-off of the metal strip 124 from the remainder of themetal coil 104. As depicted in FIG. 1, the non-contacting hold-downdevice 108 is a non-contacting hold-down roll that rotates in direction110 to apply a slight downstream tension in the metal strip 124.

The metal strip 124 can fall away from the remainder of the metal coil104 naturally due to gravity, taking a curvature. The curvature can bemonitored by a sensor 194, such as a distance sensor and/or a camera(e.g., the curvature being sensed via machine vision). The sensor 194can be coupled to a controller 192. Controller 192 can use the curvaturemeasurements to make adjustments to system 100, such as by adjusting thepay-off rate of the uncoiler 102. In some cases, adjustments can includemanipulating the position of spray headers 114, 116 of one or more ofthe set of quenching zones 112.

In some cases, the uncoiler 102 can include insulation surrounding atleast a portion of the metal coil 104 to retain heat within the metalcoil 104. In some cases, the uncoiler 102 can include a heater, such asa heated arbor, sufficient to maintain the temperature of the metalstrip 124 while the metal strip 124 is in the metal coil 104.

The uncoiled metal strip 124 can pass through a set of quenching zones112. Each of the set of quenching zones can comprise an upper sprayheader 114 and a lower spray header 116. Each spray header 114, 116 canitself comprise one or more ports through which coolant is directedtowards the metal strip. The rate of coolant flow can be controlled,such as via controller 192. The rate of coolant flow can be sufficientto reduce the temperature of the metal strip 124 by at least 100° C./sor 200° C./s.

After passing through the set of quenching zones 112, the metal stripcan pass by air knives 118 that blow excess coolant off the top of themetal strip 124. In some cases, an optional squeegee 122 can be used tofurther remove excess coolant. In some cases, a wiper 120 can be used toremove excess coolant from the bottom of the metal strip 124. In somecases, the wiper 120 is an ultra-compliant wiper.

After coolant has been removed from the metal strip 124, the metal strip124 can pass through a bridle zone 126. In the bridle zone 126, themetal strip 124 can wrap around upper bridle rolls 130 and lower bridlerolls 132 to impart a desired amount of tension on the metal strip 124downstream of the bridle zone 126, without imparting additional tensionon the metal strip 124 upstream of the bridle zone 126. In some cases,devices other than or in addition to bridle rolls 130, 132 can be usedto impart the necessary tension onto the metal strip 124. In some cases,the bridle zone 126 can comprise an easy-thread bridle. As depicted inFIG. 1, the bridle zone 126 comprises two bridle arms 128 each couplingan upper bridle roll 130 to a lower bridle roll 132. The bridle arms 128are in an operating position in FIG. 1. To thread the metal strip 124through the bridle zone 126, bridle arms 128 can be pivoted around theupper bridle rolls 130 such that the lower bridle rolls 132 arepositioned above the upper bridle rolls 130. Then, the metal strip 124can be easily passed between the upper bridle rolls 130 and lower bridlerolls 132 (e.g., the metal strip 124 can pass above the upper bridlerolls 130 and below the lower bridle rolls 132). Then, to move thebridle arms 128 back to an operating position, the bridle arms 128 canbe pivoted again around the upper bridle rolls 130 until the lowerbridle rolls 132 fully engage the metal strip 124, as depicted in FIG.1.

In some cases, the metal strip 124 can optionally pass through alubricator 134 to apply lubricant to the metal strip 124, such as tolubricate the metal strip 124 in advance of coiling the metal strip 124.

In some cases, the metal strip 124 can pass around a deflection roll136. The deflection roll 136 can redirect the metal strip 124 to beappropriately coiled by coiler 134. In some cases, the deflection roll136 can measure the flatness of the metal strip. In such cases, thedeflection roll 136 can be coupled to the controller 192 to facilitatefeedback control of the set of quenching zones 112 based on measuredflatness at the deflection roll 136. The deflection roll 136 can be aflatness measuring roll.

As depicted in FIG. 1, the metal strip 124, after being cooled and aftertension is applied, is coiled into a metal coil 140 by coiler 138. Themetal coil 140 is a warm or cold coil, at a temperature below therecrystallization temperature of the metal strip 124. In some case, themetal coil 140 is at room temperature. In some cases, the metal coil 140(e.g., the metal strip 124 after quenching) is at a temperature suitablefor warm or cold rolling.

FIG. 2 is a schematic side view of a system 200 for rapidly quenching ahot metal coil 204 for further rolling according to certain aspects ofthe present disclosure. System 200 can be similar to system 100,although with some different elements and configuration. Certain aspectsand features of system 200 can be used with system 100 whereappropriate, and certain aspects and features of system 100 can be usedwith system 200 where appropriate. The hot metal coil 204 comprisesmetal strip 224 at high temperatures (e.g., temperature at or above therecrystallization temperature of the metal strip 224).

The metal coil 204 can be unwound by an unwinder 202. The unwinder 202can unwind the hot metal coil 204 in unwinding direction 206. Anon-contacting hold-down device 208 can apply slight force to facilitatecontrolled pay-off of the metal strip 224 from the remainder of themetal coil 204. As depicted in FIG. 2, the non-contacting hold-downdevice 208 is a non-contacting hold-down roll that rotates in direction210 to apply a slight downstream tension in the metal strip 224.

The metal strip 224 can fall away from the remainder of the metal coil204 naturally due to gravity, taking a curvature. The curvature can bemonitored by a sensor, as disclosed with reference to system 100 ofFIG. 1. A controller can be used to make adjustments to system 200, suchas disclosed with reference to system 100 of FIG. 1.

In some cases, the uncoiler 202 can include insulation surrounding atleast a portion of the metal coil 204 to retain heat within the metalcoil 204. In some cases, the uncoiler 202 can include a heater, such asa heated arbor, sufficient to maintain the temperature of the metalstrip 224 while the metal strip 224 is in the metal coil 204.

The uncoiled metal strip 224 can pass through a set of preheaters 246before passing through a set of quenching zones 212. As depicted in FIG.2, the preheaters 246 are magnetic rotors that rotate and generate achanging magnetic field through the metal strip 224 sufficient toincrease a temperature of the metal strip 224 to a target temperature.In some cases, however, other types of preheaters 246 can be used, suchas direct flame heaters, infrared heaters, hot air blowers, or otherheaters.

After being heated to a consistent target temperature, the metal strip224 can be passed through the set of quenching zones 212. Each of theset of quenching zones can comprise an upper spray header 214 and alower spray header 216. Each spray header 214, 216 can itself compriseone or more ports through which coolant is directed towards the metalstrip. The rate of coolant flow can be controlled. The rate of coolantflow can be sufficient to reduce the temperature of the metal strip 224by at least 100° C./s or 200° C./s.

In some cases, a steam reclamation module 242 can be positioned adjacentthe set of quenching zones 212 to capture steam from areas near one ormore of the set of quenching zones and redirect the steam towards themetal strip 224 at a location further downstream. As depicted in FIG. 2,the steam reclamation module 242 comprises ductwork configured tocapture and redirect steam towards the metal strip 224, however thisneed not always be the case. For example, in some cases, a steamreclamation module 242 can carry steam away from the metal strip 224,through a blower, and back towards the metal strip 224. In some cases,however, the steam reclamation module 242 can collect and/or redirectsteam away from the metal coil 204 to help prevent staining of the metalstrip 224 still on the metal coil 204.

After passing through the set of quenching zones 212, the metal strip224 can pass by air knives 218 that blow excess coolant off the top ofthe metal strip 224. In some cases, an optional squeegee 222 can be usedto further remove excess coolant. In some cases, a wiper 220 can be usedto remove excess coolant from the bottom of the metal strip 224. In somecases, the wiper 220 can be an ultra-compliant wiper.

After coolant has been removed from the metal strip 224, the metal strip224 can pass through a bridle zone 226. In the bridle zone 226, themetal strip 224 can wrap around outer bridle rolls 230 and an innerbridle roll 232 to impart a desired amount of tension on the metal strip224 downstream of the bridle zone 226, without imparting additionaltension on the metal strip 224 upstream of the bridle zone 226. In somecases, devices other than or in addition to bridle rolls 230, 232 can beused to impart the necessary tension onto the metal strip 224. Asdepicted in FIG. 2, the bridle rolls 230, 232 are in an operatingposition. To easily thread the bridle zone 226, the inner bridle roll232 can be raised and the metal strip 224 can be passed above the outerbridle rolls 230 and below the inner bridle roll 232. Then, the innerbridle roll 232 can be moved back down to the position seen in FIG. 2 toengage the metal strip 224 and enter the operating position.

In some cases, the metal strip 224 can optionally pass through alubricator 234 to apply lubricant to the metal strip 224, such as tolubricate the metal strip 224 in advance of rolling the metal strip 224.

In some cases, the metal strip 224 can be directed to downstreamequipment, such as a roll stack 224 of a rolling mill. The downstreamequipment can be any suitable downstream equipment, such as downstreamequipment that requires an amount of back-tension that is greater thanthe yield strength of the metal strip 224 at the temperatures of the hotcoil 204, or downstream equipment that requires the metal strip 224 beat a temperature below that of the hot coil 204. Thus, the system 200can enable a hot coil 204 to be fed into downstream equipment previouslyunusable with hot coils 204.

As depicted in FIG. 2, the metal strip 224 entering the downstreamequipment is at a warm or cold temperature, such as a temperature belowthe recrystallization temperature of the metal strip 224. In some case,the metal coil 240 is at room temperature. In some cases, the metalstrip 224 entering the downstream equipment is at a temperature suitablefor warm or cold rolling.

FIG. 3 is a schematic block diagram of a rapid quench line 300 accordingto certain aspects of the present disclosure. Rapid quench line 300 canbe systems 100, 200 of FIGS. 1, 2. The metal strip 324 moves downstreamthrough the rapid quench line 300, from left-to-right as depicted inFIG. 3.

An uncoiler 302 can accept a hot metal coil (e.g., a metal coil at orabove recrystallization temperature) and uncoil the metal strip 324 fromthe hot coil with low tension. The uncoiler 302 can rely on gravity topay-off the metal strip 324. In some cases, the uncoiler 302 can includea non-contacting hold-down device 308 suitable to apply force to themetal coil to facilitate pay-off of the metal strip 324.

An optional non-contacting heater 346 can be positioned downstream ofthe uncoiler 302. The non-contacting heater 346 (e.g., preheater, suchas preheater 246 of FIG. 2) can be any suitable device for heating themetal strip 324 prior to quenching, such as a magnetic rotor heater. Amagnetic rotor heater can comprise a set of permanent magnets disposedon a rotor, which, when spun, can impart a temperature increase on anadjacent metal strip.

A set of quenching zones 312 can be positioned downstream of theuncoiler 302 and optional non-contacting heater 346. Each quenching zonecan comprise one or more spray headers positioned to dispense coolant onthe metal strip 324. In some cases, an optional steam reclamation module342 can be positioned to collect steam from one or more of the set ofquenching zones and redirect the steam towards the metal strip 324 tofacilitate cooling the metal strip 324, especially when the temperatureof the metal strip 324 is at or below the Leidenfrost point.

A coolant removal zone 318 can be positioned downstream of the set ofquenching zones. The coolant removal zone 318 can comprise any equipmentsuitable for removing coolant from the metal strip 324. In some cases,the coolant removal zone 318 can comprise one or more air knives. Insome cases, the coolant removal zone 318 can comprise one or moresqueegees. In some cases, the coolant removal zone 318 can comprise oneor more wipers (e.g., ultra-compliant wipers).

A bridle zone 326 can be positioned downstream of the coolant removalzone 318. The bridle zone 326 can comprise a set of bridle rolls aboutwhich the metal strip 324 can be partially wrapped to achieve adownstream tension in the metal strip 324 (e.g., a tension downstream ofthe bridle zone 326). In some cases, the bridle zone 326 can compriseeasy-threading bridle rolls.

In some cases, an optional lubricator 334 can be positioned downstreamof the bridle zone 326 to impart lubrication on the metal strip prior toreaching the downstream equipment 338.

The metal strip 324 can reach downstream equipment 338 for furtherprocessing or storage. In some cases, the downstream equipment 338 cancomprise a coiler. In some cases, the downstream equipment 338 cancomprise other equipment, such as warm or cold rolling mills. By thetime the metal strip 324 reaches the downstream equipment 338, the metalstrip will have cooled to a temperature below the recrystallizationpoint and will have tension imparted thereon (e.g., more tension thansuitable for the hot coil at the uncoiler 302).

FIG. 4 is a combination schematic block diagram 400 and temperaturegraph 401 depicting relative temperatures of a metal strip 424 passingthrough a rapid quench line according to certain aspects of the presentdisclosure. The metal strip 424 moves downstream through the rapidquench line, from left-to-right as depicted in FIG. 4. Block diagram 400can be a diagram of the rapid quench line 300 of FIG. 3. The temperaturegraph 401 is a relative graph for illustrative purposes only and is notintended to be to scale. The block diagram 400 and temperature graph 401are vertically aligned to depict the approximate relative temperaturesof the metal strip 424 as it passes through the various components ofthe rapid quench line depicted in the block diagram 400.

At the uncoiler 402, the metal strip 424 can have a temperature that isconsidered hot, such as a temperature at or above the recrystallizationtemperature 457 of the metal strip 424. In some cases, the uncoiler 402can receive a hot coil at various initial temperatures 450. In somecases, integrated heating and/or insulation in the uncoiler 402 can helpmaintain the initial temperature 450 of the metal strip 424.

In some cases, an optional non-contacting heater 446 can impartadditional heating designed to raise the temperature of the metal strip424 to a target temperature 456, despite the initial temperature 450 ofthe hot coil. In some cases, the non-contacting hold-down device 408 canimpart some amount of heat into the metal strip 424, although that neednot be the case.

Within the set of quenching zones 412, and number of quenching zones canbe used to rapidly quench the metal strip 424. As depicted in FIG. 4,four quenching zones 458, 460, 462, 464 are shown, although any numberof zones can be used. In some cases, when an optional steam reclamationmodule 442 is used, the steam reclamation module 442 can collect steamfrom upstream quenching zone(s), such as first quenching zone 458 andsecond quenching zone 460, and redirect the steam and/or humid airtowards the metal strip 424 at a location downstream of where the steamwas collected. In some cases, the steam reclamation module 442 canredirect the steam towards the metal strip 424 before, during, or aftersubsequent quenching zones (e.g., third quenching zone 462 and fourthquenching zone 464). In some cases, the steam reclamation module 442 canredirect the steam towards the metal strip 424 at a location 468 wherethe metal strip 424 is about to, is currently, or has already droppedbelow the Leidenfrost point 470.

After the set of quenching zones 412, the temperature of the metal strip424 can be at a warm or cold temperature. The temperature of the metalstrip 424 may not change significantly after the set of quenching zones412, such as when passing through the coolant removal zone 418, bridlezone 426, optional lubricator 434, or downstream equipment 438; althoughin some cases the temperature of the metal strip 424 may slowly approachroom temperature or ambient temperature. In some cases, the temperatureof the metal strip 424 after the set of quenching zones 412 can be knownas a cooled temperature 472.

FIG. 5 is a schematic side view of a steam reclamation module 542 on arapid quench line 500 according to certain aspects of the presentdisclosure. FIG. 5 depicts a portion of a rapid quench line 500 locatedbetween an uncoiler and a bridle zone. The rapid quench line 500 can berapid quench line 300 of FIG. 3.

As the metal strip 524 passes from left to right in a downstreamdirection, the metal strip can pass through several quenching zones 558,560, 562, 564, 566. Each quenching zone can comprise spray headers 514that dispense coolant 574 onto the metal strip 524. Coolant extract heatfrom the metal strip 524, especially near the first one, two, or severalquenching zones (e.g., quenching zones 558, 560, 562) will generate asubstantial amount of steam 576.

A steam reclamation module 542 can be positioned to capture steam 576and redirect the steam 576 back onto the metal strip 524. In some cases,the steam reclamation module 542 can comprise a hood 578 for collectingthe steam and ductwork 580 for redirecting the steam towards the metalstrip 524. In some cases, the steam reclamation module 542 can comprisean optional blower 582 that facilitates moving the steam 576 towards themetal strip 524 (e.g., towards the end of the ductwork 580 opposite thehood 578.

As depicted in FIG. 5, the steam reclamation module 542 redirects thesteam 576 back to the metal strip 524 at a location downstream of thefirst three quenching zones 558, 560, 562 and upstream of the last twoquenching zones 564, 566, although this need not always be the case. Thesteam reclamation module 542 can instead redirect steam 576 to the metalstrip 524 at any suitable location, including upstream or downstream ofthe location where the steam 576 is collected. However, it has beendetermined that redirecting steam 576 to the metal strip 524 adjacentto, at, and/or immediately after a location 568 where the temperature ofthe metal strip 524 is at or below the Leidenfrost point can beespecially useful.

Also depicted in FIG. 5 is a set of air knives 518 positioned above themetal strip 524 to direct air 584 onto the surface of the metal strip524 to remove coolant from the metal strip 524.

FIG. 6 is a schematic top view of a non-contacting hold-down roll 608comprising a magnetic rotor 690 according to certain aspects of thepresent disclosure. In some cases, the non-contacting hold-down roll 608can be a magnetic rotor 690. While any suitable magnetic rotor can beused, it has been determined that a magnetic rotor 690 with a chevronpattern of magnetic poles can be especially suitable for impartingconsistent (e.g., non-fluctuating) tension on the metal strip, thusminimizing the risk of damaging the fragile hot coil.

The chevron pattern depicted in FIG. 6 shows alternating north poles 686and south poles 688 distributed across the width and circumference ofthe magnetic rotor 690. In some cases, the chevron pattern is configuredsuch that for all points along the rotation of the magnetic rotor 690,the magnetic rotor 690 will always be presenting at or approximately thesame amount of magnetic flux to the metal strip. The chevron pattern canvary in overlap, gap, angle of attack, and other characteristics. Insome cases, the magnetic rotor 690 is configured to rotate in thedirection of the chevron patter (e.g., from the top of the page to thebottom of the page as depicted in FIG. 6), although that need not alwaysbe the case. In some cases, other types of patterns are used to achievea consistent tension on the metal strip.

FIG. 7 is a flowchart depicting a process 700 for rapidly quenching ahot metal coil according to certain aspects of the present disclosure.In some cases, process 700 can use the systems 100, 200 of FIGS. 1, 2 orthe rapid quench line 300 of FIG. 3.

At block 702, hot metal coil is unwound. Unwinding of the hot metal coilis performed by a low-tension unwinder. In some cases, unwinding the hotmetal coil further comprises applying non-contacting hold-down force tothe metal coil through a non-contacting hold-down device. In some cases,unwinding the hot metal coil comprises permitting the metal strip topay-off from the metal coil through the use of gravity.

At optional block 706, the metal strip can be heated (e.g., preheated)to a target temperature. In some cases, if the hot metal coil is alreadyat the target temperature, not preheating is necessary.

At block 708, the metal strip can be rapidly quenched. Rapid quenchingcan comprise lowering the temperature of the metal strip at a rate of ator at least 100° C./s or 200° C./s. Rapid quenching can involvedispensing coolant to the metal strip using one or more spray headers.In some cases, rapidly quenching the metal strip at block 708 canfurther include one or more of optional blocks 710, 712, 714. At block710, steam from one or more quenching zones can be collected. At block712, the metal strip can be quenched to a temperature below theLeidenfrost point. At block 714, steam collected from block 710 can beredirected to the metal strip. In some cases, block 714 can occurwithout block 712 first occurring. However, in some cases, block 714occurs only after the metal strip has reached a temperature below theLeidenfrost point at block 712.

In some cases, quenching the metal strip at block 708 can comprisereceiving flatness information (e.g., from a downstream flatnessmeasurement device, such as a deflection roll) and adjusting thedispensing of coolant from the spray headers to achieve a desiredflatness.

At block 716, coolant is removed from the metal strip. In some cases,removing coolant from the metal strip can comprise using any combinationof air knives, squeegees, wipers (e.g., ultra-compliant wipers), orother coolant-removing devices.

At block 718, tension is applied to the metal strip. Tension applied tothe metal strip at block 718 can be downstream tension, such that thetension does not carry up through the hot roll at the uncoiler, butrather carries through to the downstream equipment. Applying tension atblock 718 can comprise passing the metal strip through bridle rolls of abridle zone to impart tension into the metal strip.

At optional block 720, lubrication can be optionally applied to themetal strip.

The metal strip can proceed downstream to any suitable downstreamequipment. In some cases, the downstream equipment can be a coiler, inwhich case the metal strip can be coiled at block 722. The resultantmetal coil will be a warm metal coil or a cold metal coil. In somecases, other downstream equipment may be used, in which case the metalstrip may undergo other downstream processing, such as warm rolling orcold rolling.

The foregoing description of the embodiments, including illustratedembodiments, has been presented only for the purpose of illustration anddescription and is not intended to be exhaustive or limiting to theprecise forms disclosed. Numerous modifications, adaptations, and usesthereof will be apparent to those skilled in the art.

A collection of exemplary embodiments are provided below, including atleast some explicitly enumerated as “Illustrations” providing additionaldescription of a variety of example embodiments in accordance with theconcepts described herein. These illustrations are not meant to bemutually exclusive, exhaustive, or restrictive; and the disclosure notlimited to these example illustrations but rather encompasses allpossible modifications and variations within the scope of the issuedclaims and their equivalents.

Illustration 1 is a system, comprising: a low-tension unwinding unit forreceiving and unwinding a metal coil of metal strip; a non-contactinghold-down device positioned adjacent the low-tension unwinding unit toprovide force on the metal strip towards the center of the metal coilduring unwinding of the metal coil; a set of quenching zones for coolingthe metal strip, wherein the set of quenching zones provides sufficientcoolant to reduce a temperature of the metal strip by a rate of at least100° C. per second; a coolant removal unit positioned downstream of theset of quenching zones; and a bridle unit positioned downstream of thecoolant removal unit for increasing tension in the metal strip.

Illustration 2 is the system of any preceding or subsequent illustrationor combination of illustrations, wherein the low-tension unwinding unitcomprises insulation disposed to retain heat within coiled portions ofthe metal coil.

Illustration 3 is the system of any preceding or subsequent illustrationor combination of illustrations, wherein the low-tension unwinding unitcomprises a heat source for providing heat to coiled portions of themetal coil, wherein the heat source is coupled to a controller formaintaining the metal coil at or above a threshold temperature.

Illustration 4 is the system of any preceding or subsequent illustrationor combination of illustrations, wherein the non-contacting hold-downdevice comprises one or more magnets for generating a changing magneticfield through the metal strip.

Illustration 5 is the system of any preceding or subsequent illustrationor combination of illustrations, wherein the changing magnetic field isconfigured distribute the force over time across a width of the metalstrip.

Illustration 6 is the system of any preceding or subsequent illustrationor combination of illustrations, wherein the non-contacting hold-downdevice comprises a nozzle for blowing heated air against the metalstrip.

Illustration 7 is the system of any preceding or subsequent illustrationor combination of illustrations, further comprising: a flatnessmeasurement unit positioned to measure a flatness of the metal strip;and a controller coupled to the flatness measurement unit and the set ofquenching zones to adjust delivery of the coolant based on measuredflatness of the metal strip.

Illustration 8 is the system of any preceding or subsequent illustrationor combination of illustrations, further comprising a stabilizationsystem positioned upstream of the set of quenching zones to introduce awave into the metal strip.

Illustration 9 is the system of any preceding or subsequent illustrationor combination of illustrations, wherein the metal strip remainssupported without mechanical contact between the metal coil and thecoolant removal unit.

Illustration 10 is the system of any preceding or subsequentillustration or combination of illustrations, wherein the set ofquenching zones comprises a steam reclamation module for redirectinghumid air from at least one of the set of quenching zones to the metalstrip at a location downstream of the at least one of the set ofquenching zones.

Illustration 11 is the system of any preceding or subsequentillustration or combination of illustrations, wherein the locationdownstream of the at least one of the set of quenching zones is alocation where the temperature of the metal strip is at or below aLeidenfrost point.

Illustration 12 is the system of any preceding or subsequentillustration or combination of illustrations, further comprising: apre-quench heating unit positioned downstream of the low-tensionunwinding unit; and a controller coupled to the pre-quench heating unitto heat the metal strip to a target temperature prior to the metal stripentering the set of quenching zones.

Illustration 13 is the system of any preceding or subsequentillustration or combination of illustrations, wherein the non-contactinghold-down device is positioned to provide the force on the metal stripat a location at or adjacent to where the metal strip falls away fromthe metal coil due to gravity.

Illustration 14 is a method, comprising: unwinding a hot metal coilusing a low-tension unwinder, wherein unwinding the hot metal coilcomprises applying a non-contacting hold-down force to the hot metalcoil and permitting metal strip of the hot metal coil to fall away fromthe metal coil; rapidly quenching the metal strip in a set of quenchingzones, wherein rapidly quenching the metal strip comprises applyingcoolant to the metal strip to reduce a temperature of the metal strip ata rate of at least 100° C. per second; removing the coolant from themetal strip; and applying downstream tension to the metal strip.

Illustration 15 is the method of any preceding or subsequentillustration or combination of illustrations, further comprisingmaintaining an initial temperature of the hot metal coil at thelow-tension unwinder.

Illustration 16 is the method of any preceding or subsequentillustration or combination of illustrations, further comprisingpreheating the metal strip immediately prior to rapidly quenching themetal strip.

Illustration 17 is the method of any preceding or subsequentillustration or combination of illustrations, wherein applying thenon-contacting hold-down force comprises generating a changing magneticfield through the metal strip.

Illustration 18 is the method of any preceding or subsequentillustration or combination of illustrations, wherein applying thenon-contacting hold-down force comprises blowing heated air against themetal strip.

Illustration 19 is the method of any preceding or subsequentillustration or combination of illustrations, further comprising:measuring flatness of the metal strip; and adjusting delivery of thecoolant based on the measured flatness.

Illustration 20 is the method of any preceding or subsequentillustration or combination of illustrations, further comprisinginducing a wave in the metal strip without contacting the metal strip.

Illustration 21 is the method of any preceding or subsequentillustration or combination of illustrations, further comprising:capturing steam from at least one of the quenching zones; andredirecting the captured steam towards the metal strip.

Illustration 22 is the method of any preceding or subsequentillustration or combination of illustrations, wherein redirecting thecaptured steam comprises redirecting the capture steam towards the metalstrip at a location where a temperature of the metal strip is at orbelow the Leidenfrost point.

1. A system, comprising: a low-tension unwinding unit for receiving andunwinding a metal coil of metal strip; a non-contacting hold-down devicepositioned adjacent the low-tension unwinding unit to provide force onthe metal strip towards the center of the metal coil during unwinding ofthe metal coil; a set of quenching zones for cooling the metal strip,wherein the set of quenching zones provides sufficient coolant to reducea temperature of the metal strip by a rate of at least 30° C. persecond; a coolant removal unit positioned downstream of the set ofquenching zones; and a bridle unit positioned downstream of the coolantremoval unit for increasing tension in the metal strip.
 2. The system ofclaim 1, wherein the low-tension unwinding unit comprises insulationdisposed to retain heat within coiled portions of the metal coil.
 3. Thesystem of claim 1, wherein the low-tension unwinding unit comprises aheat source for providing heat to coiled portions of the metal coil,wherein the heat source is coupled to a controller for maintaining themetal coil at or above a threshold temperature.
 4. The system of claim1, wherein the non-contacting hold-down device comprises at least oneof: one or more magnets for generating a changing magnetic field throughthe metal strip, or a nozzle for blowing heated air against the metalstrip.
 5. The system of claim 4, wherein the changing magnetic field isconfigured distribute the force over time across a width of the metalstrip.
 6. (canceled)
 7. The system of claim 1, further comprising: aflatness measurement unit positioned to measure a flatness of the metalstrip; and a controller coupled to the flatness measurement unit and theset of quenching zones to adjust delivery of the coolant based onmeasured flatness of the metal strip.
 8. The system of claim 1, furthercomprising a stabilization system positioned upstream of the set ofquenching zones to introduce a wave into the metal strip.
 9. The systemof claim 1, wherein the metal strip remains supported without mechanicalcontact between the metal coil and the coolant removal unit.
 10. Thesystem of claim 1, wherein the set of quenching zones comprises a steamreclamation module for redirecting humid air from at least one of theset of quenching zones to the metal strip at a location downstream ofthe at least one of the set of quenching zones.
 11. The system of claim1, wherein the location downstream of the at least one of the set ofquenching zones is a location where the temperature of the metal stripis at or below a Leidenfrost point.
 12. The system of claim 1, furthercomprising: a pre-quench heating unit positioned downstream of thelow-tension uncoiling unit; and a controller coupled to the pre-quenchheating unit to heat the metal strip to a target temperature prior tothe metal strip entering the set of quenching zones.
 13. The system ofclaim 1, wherein the non-contacting hold-down device is positioned toprovide the force on the metal strip at a location at or adjacent towhere the metal strip falls away from the metal coil due to gravity. 14.A method, comprising: unwinding a hot metal coil using a low-tensionunwinder, wherein unwinding the hot metal coil comprises applying anon-contacting hold-down force to the hot metal coil and permittingmetal strip of the hot metal coil to fall away from the metal coil;rapidly quenching the metal strip in a set of quenching zones, whereinrapidly quenching the metal strip comprises applying coolant to themetal strip to reduce a temperature of the metal strip at a rate of atleast 100° C. per second; removing the coolant from the metal strip; andapplying downstream tension to the metal strip.
 15. The method of claim14, further comprising maintaining an initial temperature of the hotmetal coil at the low-tension unwinder.
 16. The method of claim 14,further comprising preheating the metal strip immediately prior torapidly quenching the metal strip.
 17. The method of claim 14, whereinapplying the non-contacting hold-down force comprises at least one of:generating a changing magnetic field through the metal strip; or blowingheated air against the metal strip.
 18. (canceled)
 19. The method ofclaim 14, further comprising: measuring flatness of the metal strip; andadjusting delivery of the coolant based on the measured flatness. 20.The method of claim 14, further comprising inducing a wave in the metalstrip without contacting the metal strip.
 21. The method of claim 14,further comprising: capturing steam from at least one of the quenchingzones; and redirecting the captured steam towards the metal strip. 22.The method of claim 21, wherein redirecting the captured steam comprisesredirecting the capture steam towards the metal strip at a locationwhere a temperature of the metal strip is at or below the Leidenfrostpoint.